Fusible link



June 17, 1930.

A. c. RowLEY 1,765,243

FUSIBLE LINK Filed June 21, 1928 Mew.

Patented June 17, 1930y UNITED sfrrs ARTHUR C. ROWLEY, OF PHILADELPHA,PENNSYLVANA, ASSEGNOR TO GLOBE 4"rar eine AUTOMATIC SPRINKLERCOMPANY,'0F PHLADELPI-IIA, PENNSYLVANA, A COR- PORATION OF PENNSYLVANIAf FUSIBLE Limi` y Applicationv filed. June 21, 1928. Serial1\To.f287,276.

The principal object of this invention is yto provide a fusible linkwhich shall be gening to separate the said parts comes upon the `fusiblecomposition.

The foregoing and other desirable ends I accomplish by means of theconstruction illustrated in the attached drawings, in Which: Figures land 2 are views in perspective of the interlocking members forming apartof my device;

Fig. 3 is a vievs7 in perspective of the housing for said interlockingmembers, which housing also functions to retain the fusible medium; and

Fig. l is a longitudinal sectional View through the assembled link. v

Referring to the draWings,'my device in a preferred form comprises apair of members 1 and 2 Which may be identical in form and which areadapted to interlock yieldingly to form a mechanical union which underconditions hereinafter set forth can be broken to permit longitudinalseparation. As shown in Figs. l and 2 the interlocked separable elementsare formed with an eyelet 3 at one end from which extend equal resilientarms 4t and 5. these arms Where they jointhe eyelet being close togetherand diverging slightly to a point adjacent their extremities from Whichpoint they converge so that their extremities touch or lie closelyadjacent. These elements are adapted to be telescoped, as shovvn in Fig.4, in which condition the inturned ends of each element close behind therestriction at the base of the arms of the other element to form amechanical interlock which can be broken only bythe spreading orspringing apart of the arms of the respective elements. Vith theaiioredescribed construction, application of a sumcient tensicnal lorcetending to draw the elements apart longitudinally Will result in thetransverse separation ci the ends of the arms l and 5, therebydestroying the interlock and permitting the elements to separate.`rllhese elementsv mayv suitably be formed-of resilient Wire, and itvvill'be apparent that the resistance of the arms to separation under' atensional force tending to draw the elements apart longitudinally may begoverned by the material of which 'the elements are made and by theangle at which" the extremities of the arms 4l and 5 con verge. 'l heelements maybe so made that a comparatively light resistance totransverse spread-` ing or the arms Will counteract acomparatively heavyforce tending to'draw the elements apart longitudinally. Preferably, theWire or other resilient material of which the members l and 2 are formedis ci rectangular cross section, although this is not essential.

n'conj unction vvitli the elements land 2, l provide a housing in theform oit' a `sleeve 6, shown in Fig. 3, Which in assembly and as e shownin Fig. er surrounds the interlocked portions of the saidl elements. The.inner diameter of the sleeve4 is sufficiently greater 'than the Widthvof the elements l and 2 to permit separation -ot the arms 4 and 5 to'anextent releasing the elements from each other. In assembly, the housing6 is iilled with the Jfusible compound 7 which entirely surrounds theinterlocked parts of the'elements l and 2 as illustratedand whichfunctions kto resist the transverse spreading apart ofthe arms i and 5of the elements and 2,which action is necessary as set-forth abovebetere the links can separate longitudinally. The ilusible compound isbacked and protected by the housing l6., and it Will be apparent thatthe compressive strength kof the compound may bel relatively low in alink capable ci supporting substantial `Weights Without separationexcept as the fusi-ble compound is aii'iected by excessive temperatures.rlhe mechanical interlock between the links isa thoroughly strong oneand the transverse component of the force which tends to pull theelements ofthe link apart longitudinally isv so relatively small. thatthe link is capable `of supportin relatively great Weights. With arectangular cross section as set forth above, a fiat and relatively Widesurface is presented to the fusible material Which affords an effectivebearing and largelyavoidsany tendency for the arms to Wedge their Waythrough the material. Obviously, a flat bearing surface may be obtainedby other than a rectangular cross section. Y f

lVhile many forms of fusible compounds maybe used in my device, it isparticularly Well suited to alphamononitro-naphthalene This material,While having` a relatively lon7 melting point, maintains its integrityWith practically no change until the melting` point is reached, and is,therefore, Well adapted to prevent the transverse spreading of the armsof the 4elements l and 2 until the melting point hasbeen approximatelyreached. There is no tendency for this material to creep or lose itshardness until the melting point has been yapprosimately reached, as inthe metallic fusible alloys heretofore generally c used in devices of.this character. y

In assembly vthe link, the elements l and 2 are inserted in oppositeends of the housing 6 and are telescoped as illustrated in Fie: l. rlfhetelescoping operation is assisted by the Vy-shaped formation of the endsof the elements land 2 Where the extremities of the arms come together,which causes the arms l and 5 to separate with slight resistance whenthe parts are pushed toward and against each other. Thereafter thefusible compound in liquid state .is poured into the housing until thelatter is filled, and is solidified byrcooling. Other types of fusiblecompound may be pressed 'into the housing in solid condition.

My device is capable of use for any purpose Where fusible links haveheretofore been employed, such for example as in fire doors, skylightcontrols,quick-opening or -closing valves and control of Ventilatingfans, Snc.

It is particularly desirable by reason vof its high efficiency andrelatively low temperature factor. The device also is simple in form andextremely easy to manufacture. Y

' l claim I l. In a fusible link, a pair of elements comprising meansfor yieldingly interlocking one with the other, a housing for saidelements, and a fusible material Within the housing for normallypreventing the yielding of said elements and to thereby maintain-saidinterlock. 2. A fusible link comprising interlocking elements havinglparts yieldable transversely under a predetermined strain upon saidelements to vbreak said interlock, a housingl for said elements, andheat responsive means in said housing normally preventing` saidtransverse yielding.

3. A fusible link comprising longitudinally Y interlock. f Y

ARTHUR C.; ROVLEY.

